RINDGE - Authorities are still searching for the cause of an air-quality alert at a Market Basket in Rindge, where at least 10 people were transported to hospitals.Lt. Tom Redin of Southwestern New Hampshire District Fire Mutual Aid said the store was evacuated and a haz-mat team from the Keene Fire Department was en route to the store Sunday night.Redin says 10 people were taken to hospitals for respiratory and breathing problems. The source was still not known about 2 1/2 hours after the emergency call."They're still investigating at the store to figure out what caused this at the time," Redin said.